1. Field of the Invention
The present invention relates to a gas circuit breaker installed in a substation or a switching station.
2. Description of the Related Art
A technology disclosed in Japanese Patent Application Laid-Open No. 2003-009318 is generally related to a 168-kV gas circuit breaker, that is, a high-voltage gas circuit breaker, for installing in a substation or a switching station, and specifically to transportation of the 168-kV gas circuit breaker. The disclosed 168-kV gas circuit breaker includes a base, three grounded tanks installed with two bushings each, an operation box housing three operating mechanisms, and a controlling box. The grounded tanks, the operation box, and the controlling box are mounted on the base to form a main body. At the time of transportation, the 168-kV gas circuit breaker is dismantled into the main body, a frame on which the main body is mounted, and a cable protection duct.
Because the gas circuit breaker disclosed in the Japanese Patent Application Laid-Open No. 2003-009318 is the high-voltage 168-kV gas circuit breaker, if the controlling box is located as high as the grounded tanks and the operation box, a distance between the controlling box and the bushings is sufficient for insulation, that is, no problems occur even while the gas circuit breaker is in operation.
However, in an extra high-voltage gas circuit breaker (for example, 362-kV gas circuit breaker) from which long bushings extend, the controlling box is required to be located lower than the grounded tanks and the operation box to ensure a sufficient insulation distance between the bushings and the controlling box. The operation box is called an upper housing and the controlling box is called a lower housing. When a conventional extra high-voltage gas circuit breaker is to be transported, it is to be dismantled into different parts such as a main body formed from grounded tanks installed with bushings and the upper housing both placed on the base, a frame, the lower housing, a gas pipe, and an electric conduit so that the conventional extra high-voltage gas circuit breaker is within the height limit appropriate for transportation.
Such type of gas circuit breaker is required to be manufactured and assembled in the factory before transportation to a substation where the gas circuit breaker works. However, in the case of the extra high-voltage gas circuit breaker, the lower housing, the gas pipe, and the cable duct are detached from the main body at transportation. That is, the gas circuit breaker for an extra high-voltage is transported in a state dismantled into the main body configured to have the grounded tanks installed with the bushings and the upper housing both mounted on the base, the frame, the lower housing, the gas pipe, and the cable duct. Therefore, the gas circuit breaker that is once assembled at the factory is dismantled for transportation after electrical inspection and gas leak inspection. Thereafter, the gas circuit breaker is reassembled at the substation.
Because the number of dismantled units is large, it takes long time to assemble the gas circuit breaker that is transported to the substation. Moreover, the electrical inspection and the gas leak inspection are to be conducted again, which causes the installation work to take longer.